T  A 


GIFT  or 


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REPORTS 


TATE  ENGINEER 


BOARD  OF  DIRECTORS  OF  DRAIXAGE  DISTRICT  W.  1, 


No.  1— Drainage  Works  for  tlie  District. 

No.  2— Dams  for  Impounding-  Mining  Detritus. 


,      Ji-ily,    188  0 


SACRAMENTO: 

STATE   OFFICE   :   I   :  J.  D.  YOUXG,  SUPT.  STATE  PRINTING. 

.  .1880. 


^^ 


I'  K  I. 


GIF' 


THE  WORKS  OF  DRAINAGE 


SACRAMENTO  VALLEY, 


Sacramexto,  June  25th,  1880. 

Hon.  Board  of  Directors,  Drainage  District  No.  1: 

Gextlemex:  You  have  been  cailed  upon  to  carry  forward  such 
works  of  drainage  as  may  be  practicable  and  deemed  necessary  for 
the  territory  now  known  as  Drainage  District  No.  1,  and  I,  as  State 
Engineer,  am  required  to  propose  plans  for  and  supervise  the  execu- 
tion of  these  works. 

The  7-epo-rt  to  the  State  Drainage  Commission.- 

The  circumstances  and  views  which  have  led  to  and  governed  in 
the  formation  of  this  district,  are  set  forth  in  a  report  made  by  myself 
to  the  State  Board  of  Drainage  Commissioners,  under  date  of  May 
twenty-sixth,  eighteen  hundred  and  eighty,  and  which  has  been  pub- 
lished, together  with  a  copy  of  the  record  of  the  minutes  of  the  pro- 
ceedings of  that  Board,  had  at  a  meeting  held  on  the  twenty-eighth 
of  May. 

Drainage  District  No.  1. 

Your  district  embraces  all  of  the  Sacramento  Valley  in  which  it 
will  be  necessary,  as  far  as  can  now  be  seen,  to  execute  works  of 
drainage,  except  some  of  the  low  lands  in  the  delta  w^hich  is  common 
to  the  San  Joaquin  as  well  as  the  Sacramento  River. 

The  report  to  the  Legislature. 

In  a  general  way,  the  drainage  of  this  district — the  Sacramento 
Valley — has  been  discussed  by  me  in  Parts  II  and  III  of  my  report 
to  the  Legislature,  under  date  of  Januarj^  tenth,  eighteen  hundred 
and  eighty.  To  avoid  much  repetition  of  argument  in  detail,  I  shall 
herein  only  briefly  summarize  the  practical  conclusions  at  large  on 
this  topic,  and  ask  your  attention  to  the  papers  referred  to,  for  the 
discussions  which  have  led  to  them.  The  broad  facts  in  the  case  are 
as  follows: 

Facts  concerning  the  rivers. 

First — Generally,  throughout  its  course,  the  channel  of  the  Sacra- 
mento River  as  the  main  drain,  and  that  of  the  Feather  as  its  chief 

332'743 


aiixiliar}^  in  t'Heir  prefsent  condition,  are  incapable  of  affording  pas- 
sage for  the  waters  of  ordinary  flood  volume  without  subjecting  a 
large  portion  of  the  great  low-land  basins  and  island  swamps  to 
inundation. 

^'eco?<(/ — The  regimen  of  the  Sacramento  River  is  bad;  its  channel 
is  of  very  uneven  capacity  in  proportion  to  the  demand  for  waterway, 
in  the  succeeding  great  divisions  thereof,  besides  having  serious  local 
obstructions  to  flood  flow. 

Tliird — These  defects,  general  and  local,  have,  in  a  degree,  always 
existed,  but  they  have  been  largely  developed  of  late  years  from  causes 
still  present  or  at  work.  The  detritus  from  the  mines  is  fllling  the 
lower  Sacramento  River  and  its  principal  tributaries,  and  an  injudi- 
cious location  of  levees  has  unduly  limited  the  width  of  flood  water- 
way at  important  points  and  for  long  stretches  of  channel. 

Preservation  of  the  rivers. 

It  is  desired  to  preserve  these  river  channels.  By  the  passage  of  the 
law  under  which  we  are  called  upon  to  act,  the  State  has  signifled  her 
realization  of  the  importance  of  thus  fostering  the  interests  more 
directly  affected  by  their  deterioration,  as  well  as  those  dependent 
upon  the  causes  which  in  great  measure  produce  this  result. 

The  Act  to  promote  drainage. 

It  is  the  object,  as  I  understand  the  measure,  to  promote  drainage — 
as  the  title  of  the  Act  implies — in  accomplishing  which  it  is  necessary 
to  do  away,  as  far  as  possible,  with  the  evil  results  of  the  flow  of  detritus 
from  the  mines,  and  to  construct  or  develop  water-way  for  the  floods. 
Furthermore,  it  is  expected  that  the  accomplishment  of  this  end  will 
improve  the  navigation  of  the  rivers  and  will  facilitate  the  reclama- 
tion of  swamp  lands  in  the  valleys  adjacent,  because  it  would  be  im- 
possible to  attain  the  primary  object  without  doing  much  which  will 
tend  towards  those  kindred  thereto. 

GENERAL   DRAINAGE   PLANS. 

Two  general  lines  of  action  for  the  engineering  solution  of  the  river 
problems  presented  are  frequently  brought  forward.  They  rest 
respectively  upon  what  may  be  termed  the  Conservation  and  the 
Distribution  theories  of  river  improvement. 

The  Outlet  or  Distribution  ti'eatment. 

To  carry  away  the  waters  of  flood  it  has  been  proposed  to  supple- 
ment the  river  waterway  by  the  construction  of  an  artiflcial  channel 
or  channels  on  the  route  down  the  valley  to  the  bay,  thus  effecting  a 
division  of  the  waters,  and,  according  to  the  arguments  of  the  advo- 
cates of  this  plan,  producing  a  lowering  of  flood  elevations  and  a 
shortening  of  high  water  periods.  This  is  the  plan  based  upon  the 
theory  that  the  greater  number  of  channels  in  which  the  waters  run 
the  less  will  be  their  flood  elevations — a  theory  which  I  have  called 
the  Distribution  theory,  because  of  the  distribution  of  the  waters 
amongst  several  channels. 

In  the  report  spoken  of,  I  have  discussed  this  plan  of  outlet  canals, 
and  have  expressed  the  opinion  that  it  would  not  afford  the  desired 
relief  from  excessive  flood  heights,  but,  on  the  contrary,  its  primary 
result  would  be  to  bring  about  a  further  deterioration  of  the  channel 


of  the  main  river  and  impair  its  usefulness  as  a  flood-carrying  and 
navigable  stream.  I  am  led  to  tliis  conclusion  by  the  results  of  expe- 
rience had  in  river  improvements  elsewhere,  the  records  of  whicli  I 
liave  examined,  and  by  the  behavior  of  this  stream  itself  under  con- 
ditions observed  during  the  past  two  years. 

The  conclusion  rests  upon  the  ojnnion  now  quite  generally  enter- 
tained by  engineers,  and  based  upon  practical  observation  as  well  as 
sound  principles,  that  the  division  of  the  waters  of  a  sediment-bearing 
river  results  in  the  formation  of  bars  in  the  channel  below  the  points 
of  diversion,  and  ultimately  in  the  permanent  contraction  of  the 
waterway  in  the  proportion  which  the  volume  of  water  diverted  bears 
to  the  volume  formerly  carried  by  the  channel.  The  onl}^  exception 
to  this  rule  is  to  be  found  within  the  influence  of  heavy  tidal  action, 
and  where  other  conditions  are  present  favorable  to  the  tidal  influence. 

The  Conservation  treatment. 

Holding  this  opinion,  I  have  recommended  the  alternative  course 
— a  sjjstematic  treatment  of  the  river  channel  itself  throughout,  with 
the  view  of  developing  its  greatest  possible  carrying  capacity,  and  of 
maintaining  it  in  good  navigable  condition.  This  plan  rests  upon 
the  idea  that  the  greater  the  volume  of  water  in  a  channel  the  less 
may  be,  and  generally  is,  its  grade  or  slope,  and  hence  a  conservation 
of  waters  in  a  channel  having  a  movable  bottom  w^ill  tend  to  reduce 
its  slope  and  lower  its  flood  elevations  by  scouring  out  the  bottom 
material.  This  I  have  called  the  Conservation  theory  of  river  im- 
provement. 

The  lower  Sacramento  River  and  its  principal  tributary,  the 
Feather,  have  beds  most  readily  moved  by  the  action  of  the  current, 
and  the  ujDper  Sacramento  has  a  channel  which  can  be  greatly  im- 
proved by  work  hereafter  to  be  discussed. '  Hence  I  have  expressed 
the  "opinion,  after  an  examination  and  measurement  in  detail,  that 
their  development  can  be  carried  forward  to  a  stage  at  which  capacity 
would  be  afforded  for  the  passage  of  all  ordinary  floods  ;  but  I  have 
said  that  the  w^ork  must  be  one  for  a  series  of  years,  and  that  from 
the  flrst,  the  great  supplies  of  sand  which  are  brought  down  the 
mining  torrents,  must  be  prevented  from  entering  the  larger  streams 
of  the  valley. 

A  general  plan  of  operations,  according  to  the  Conservation  treat- 
ment, was  sketched  out  in  the  report  to  the  Legislature,  heretofore 
spoken  of,  and  it  remains  now  to  classify  and  mention  the  principal 
works  which  it  will  be  necessary  to  prosecute,  and  this  I  now  do,  so 
far  as  these  can  be  designated  at  present. 

Some  provisions  in  the  law. 

In  classifying  and  pointing  out  the  works  which  may  be  carried 
forward  under  your  direction,  I  hold  in  view  the  provision  of  the  law 
which  stipulates  that  "  all  moneys  raised  ^  ^  ^  ^  shall  be  used 
exclusively  for  the  construction  of  dams  for  impounding  the  debris 
from  the  mines,  *  *  *  and  for  the  rectiflcation  of  river  channels 
in  which  said  debris  flows  within  the  drainage  district,"  etc.    (Sec.  24.) 

This  stipulation  would  seem  to  preclude  the  construction  of  any 
such  w^ork  as  a  relief  canal,  and  the  building  of  levees  for  the  protec- 
tion of  lands  from  inundations,  but  it  does  not  prohibit  the  prosecu- 
tion of  any  w^ork  which  may  be  necessary  for  the  impounding  of 
debris  or  the  rectification  of  river  channels  in  wdiich  the  debris  flows. 


6 

I  liold  that  the  works  hereinafter  designated  are  necessary  to  effect 
these  ends,  within  the  district  whose  drainage  system  you  are  called 
upon  to  improve,  as  I  will  endeavor  to  show  in  each  case. 

CLASSIFICATION   OF   WORKS. 

Two  general  classes  of  works  must  be  undertaken:  the  first,  to 
withhold  the  sands  from  the  main  stream  and  private  property  ;  the 
second,  to  improve  the  channels  of  those  streams  so  that  they  will 
maintain  themselves,  with  a  small  amount  of  attention,  subsequently^ 
in  the  best  possible  condition  as  flood-carrying  and  navigable  chan- 
nels. These  works  may  be  somewhat  more  definitely  classified  as 
follows: 

Arresting  thefloio  of  the  detritus — dams. 

First — Works  calculated  to  check  the  flow  of  sands  into  the  navi- 
gable rivers  from  the  mining  streams.  These  w411  consist  of  dams 
composed  of  rough  stone,  b^^ushwood,  and  gravel,  or  a  combination  of 
these  materials,  as  the  case  may  be,  located  and  proportioned  as  may 
seem  most  favorable  in  each  case. 

Structures  of  this  character  should  first  be  projected  where  the  best 
conditions  are  presented  for  the  test  of  their  efficiency  at  a  reasonable 
outlay  of  money.  Other  things  being  equal,  the  lower  down  such 
works  can  be  brought  on  the  tributary  streams,  the  more  certain  they 
will  be  of  accomplishing  their  object,  and  at  small  outlay  of  money; 
for  lighter  grades  are  found  upon  which  to  impound  or  rest  the  ma- 
terials stored,  longer  crested  dams  are  possible  (over  which  the  water 
will  pour  to  a  less  depth  and  with  less  force)  and  less  material  will 
be  left  below  the  site  unguarded  or  unrestrained. 

The  Yuba  and  the  Bear  Rivers  present  the  best  opportunities  for 
this  class  of  work,  and  the  localities  where  it  is  most  needed. 

In  a  special  report  to  be  submitted  concerning  each  of  these  stream s» 
I  will  make  recommendations  and  submit  plans  for  the  works  which 
I  deem  advisable  to  undertake  at  once  upon  them. 

Preventing  the  spread  of  the  detrntus — levees. 

Second — Works  calculated  to  guard  against  the  spread  of  the  waters 
from  the  mining  streams,  and  consequent  destruction  of  the  channels 
in  which  they  flow. 

These  will  consist  of  levees,  and  those  already  in  existence  should 
be  strengthened,  raised,  or  protected  from  erosion,  as  may  be  neces- 
sary in  each  case,  or  new  levees  may  be  constructed  where  none  are 
now  in  existence  or  the  old  ones  are  not  worth  adhering  to. 

The  law  provides  that  such  works  as  are  necessary  for  the  rectifica- 
tion of  the  river  channels  in  which  said  debris  flows,  may  be  con- 
structed. Levees  on  each  side  of  such  streams  as  the  Yuba  and  Bear 
Rivers,  for  instance,  may  be  necessary  to  prevent  the  spread  of  their 
waters.  Now  the  spreading  of  these  waters  results  in  the  deposit  of 
their  sediment  and  the  obliteration  of  the  river  channels.  It  is  nec- 
essary, therefore,  in  order  to  rectify  these  channels,  that  the  waters  be 
not  allowed  to  spread,  hence  levees  are  necessary;  and  hence,  I  pre- 
sume, you  will  undertake  this  class  of  work. 

Again,  the  Yuba  and  Bear  River  regions  present  the  theater  of 
most  needed  action,  though  along  the  shores  of  the  Feather,  also,  as 
well  as  on  the  lower  course  of  the  American,  existing  levees  must  be 


maintained,  if  proper  control  is  to  be  exercised  over  their  waters;  and 
the  river  channels  preserved  or  improved.  In  a  special  report  con- 
cerning work  which  should  be  undertaken  this  season,  I  will  speak 
more  definitely  of  this  subject. 

ChccMng  the  snonling  of  the  main  rivers. 

Third — Works  calculated  to  guard  against  the  further  deterioration 
of  the  channels  of  the  larger  rivers,  and  exert  an  influence  towards 
their  complete  rectihcation. 

These  will  have  for  their  immediate  objects,  (1st)  the  prevention  of 
heavy  bank  caving,  except  where  such  may  be  desirable  to  effect  some 
beneficial  change  in  the  stream  alignment;  and  (2d),  the  closing  or 
partial  closing  of  all  deep  channels  of  escape  for  water  from  the  main 
stream  (such  as  the  crevasses  through  the  bank  of  the  Sacramento 
River  below  Knight's  Landing  to  Sacramento  City),  so  far  as  these 
can  be  closed  without  causing  other  ruptures  and  the  creation  of  other 
lines  of  overflow. 

Bank-  caving — spur  dikes  and  retetevient. 

The  first  one  of  the  objects  just  mentioned,  is  to  be  attained  by  the 
construction  of  spur  dikes  of  brush,  stone,  gravel,  sand-boxes,  or  piling, 
or  a  combination  of  some  of  these,  to  deflect  the  current  from  the 
bank  attacked  and  create  deposits  for  new  bank  lines.  The  Sacra- 
mento Eiver  above  Colusa  presents  the  field  where  it  will  be  most 
necessary  to  conduct  this  class  of  work,  for  there  are  a  number  of 
points  where  the  river  channel  is  of  exceedingly  bad  trend,  owing  to 
this  caving  of  banks,  and  radical  changes  of  the  channel  are  threat- 
ened to  the  detrim^it  of  its  uniform  regimen  as  a  whole,  and  conse- 
quent defeat  of  its  rectifications — a  leading  object  of  the  whole 
measure. 

Deep  outlets — gradual  closure,  overflow  iveirs. 

The  second  object  of  this  class  of  work  is  to  be  attained  by  entirely 
closing  the  breaks  in  existing  levees,  so  far  as  it  is  safe  so  to  do,  with 
earth  embankments,  and  by  partially  closing  the  remaining  openings 
—the  deeper  cuts  at  least — with  structures  of  brush,  timber,  and 
gravel  or  stone,  over  which  the  water  may  pour,  when  it  reaches  a 
certain  safe  flood  elevation,  without  damage  to  the  structure  itself. 

I  consider  these  overflow  weirs  an  essential  feature  of  the  plan  of 
improvement  proposed,  for  the  river  from  Knight's  Landing  to  Sac- 
ramento City,  and  it  may  be  necessary  to  apply  them  elsewhere  along 
its  course  also.  If  there  were  means  enough  at  command  to  construct 
at  once  such  strong  and  large  levees  along  the  river,  and  to  do  such 
other  Avork  as  would  facilitate  its  scouring  out  and  rectification,  by 
the  holding  of  all  flood  water,  then  the  weirs  might  be  dispensed 
with.  But  this  would  necessitate  an  outlay  beyond  the  means  at  all 
likely  to  be  at  your  disposal,  and  as  the  water  will  undoubtedly  escape 
during  floods  at  various  points  for  some  time  to  come,  I  propose 
that  it  shall  find  passage  at  such  points  and  in  such  manner  as  w^ill 
do  least  harm,  and  only  at  such  times  as  the  river  channel  may  not 
be  able  to  carry  all  presented  to  it. 

Concerning  the  extent  of  this  class  of  work  to  be  done,  the  location 
and  character  of  construction  for  the  proposed  weirs,  I  will  shortly 
submit  a  special  report  for  your  consideration. 


8 

Promoting  the  deepening  of  the  main  rivers. 

Fourth — Works  calculated  to  cause  the  removal  of  bars  in  the  river, 
where  they  exercise  an  unfavorable  influence  upon  the  uniformity  of 
its  capacity,  and  thus  prevent  general  deepening  by  the  scouring 
action  of  its  current. 

Several  notable  bars  of  this  character  and  effect  exist  in  the  Sacra- 
mento River  below  the  mouth  of  the  Feather,  and  they  are  found,  as 
is  usual  in  such  cases,  where  the  bank  lines  are  far  apart  or  where 
some  irregularities  of  alignment  in  the  banks  exist  and  cause  a  check 
or  eddy  in  the  current  and  a  deposit  of  sand  as  a  result. 

Removal  0/  bars — spur  dikes,  parallel  dikes. 

Their  removal  is  to  be  accomplished  by  the  construction  of  spur 
dikes,  or  perhaps  similar  works  parallel  to  the  current — according  to 
the  circumstances  in  each  case— of  brush,  stone,  gravel,  or  timber 
piling,  or  a  coinbination  of  these,  in  sucli  manner  as  to  cause  a  con- 
centration of  the  current  upon  a  judicious  alignment,  by  contracting 
the  channel  to  its  normal  width,  and  guiding  the  water  in  such  nar- 
rowed channel  up  to  an  elevation  equivalent  to  a  low  flood  stage. 

I  may  say  here,  by  way  of  parenthesis,  that  dredging  may  be 
required  in  some  of  the  bars,  but  this  result  is  not  expected  generally. 

As  in  the  case  of  the  last  mentioned  class  of  works,  these  constitute, 
in  my  opinion  at  least,  a  most  important  feature  in  the  plans  to  rectify 
the  channel  of  the  river,  and,  as  their  position  in  this  enumeration 
implies,  should  be  carried  forward  before  the  final  and  completed 
effort  is  made  to  force  scouring  action  by  altogether  confining  the 
flood  waters;  because  a  condition  of  channel  approximating  a  perfect 
regimen  for  the  river  is  essential  to  success  in, confining  its  flood 
waters,  and  to  approach  such  a  condition  local  obstructions  must  be 
removed. 

Correcting  the  alignment  of  the  main  rivers. 

Fifth — Works  calculated  to  straighten  the  river  channel  where,  by 
reason  of  sudden  and  irregular  turns  or  bends,  a  serious  check  is  given 
to  flood  movements,  and  where  the  slope  or  grade  of  the  country  is 
less  than  that  through  which  the  river  generally  courses. 

Under  the  proper  circumstances  a  channel  may  be  benefited  in 
this  way  by  making  sudden  and  sharp  bends  less  abrupt  and  angular, 
or  by  opening  a  new  channel  through  behind  such  a  sinuosity  of  the 
river  course,  which  latter  works  are  termed  cut-offs. 

Where  a  bend  is  very  abrupt,  it  may  be  made  less  so.  Training  the 
current  against  it  by  the  use  of  spur  dikes  constructed  on  the  opposite 
shore  above,  crowding  the  current  out  of  the  opposite  bay  by  the  con- 
tinuation of  the  -series  of  spur  dikes  from  above  down  into  it,  and 
blowing  down  the  point  from  time  to  time  to  be  w^ashed  away,  as  may 
be  necessary,  will  accomplish  this  result. 

Cut-offs —  Upper  Sacramento  River. 

To  cause  the  complete  elimination  of  a  bend  from  the  course  of  the 
channel,  cut-offs  are  made  by  clearing  the  path  of  the  proposed  new 
channel,  cutting  out  a  canal  down  to  near  low  w^ater  mark  upon  its 
route,  to  a  width  of  one  tenth  to  one  fifth  that  of  the  proposed  chan- 
nel, and  forcing  the  currents  of  floods  to  enter  the  cut  by  a  proper 
arrangement  of  spur  dikes  or  other  guiding  works  if  it  be  necessary, 


9 

and  from  time  to  time  gradually  closing  the  old  channel  as  the  new 
one  becomes  efficient  by  washing  out. 

The  Sacramento  River,  between  Colusa  and  Butte  Slough  and  the 
mouth  of  Feather  River,  is  a  very  tortuous  stream,  and  narrow  in 
proportion  to  its  dimensions  above  and  below.  The  grade  of  the 
country  through  which  it  flows  for  this  division  is  much  less  than 
that  above.  Its  capacity  is  much  less  than  that  of  the  divisions  above 
and  below  under  existing  circumstances,  and  this  is  largely  occasioned 
by  excessive  bend  resistance  due  to  the  sudden  turns  in  its  channel 
and  general  tortuous  course. 

To  bring  the  river  to  a  good  regimen  it  will  be  necessary,  in  my 
opinion,  to  diminish  the  abruptness  of  the  most  acute  turns  in  this 
part  of  the  channel,  and  shorten  it  also  by  making  some  cut-offs. 
These  can  be  carried  out  at  a  reasonable  outlay  of  money,  in  a  num- 
ber of  instances. 

Prevention  of  cut-offs — Upper  Sacramento  River. 

While  it  is  necessary  that  the  river's  course  should  be  straightened 
through  the  divisions  from  Butte  Slough  to  the  mouth  of  Feather,  I 
hold  that  above  Butte  Slough,  where  the  formation  of  cut-offs  is  most 
easy,  and  where  they  do  occur  naturally  sometimes,  all  straightening 
of  the  channel  should  be  prevented,  because  the  river  is  already  of 
much  greater  grade  and  cross  sectional  dimensions  than  it  is  in  the 
division  next  below,  where  it  is  necessary,  by  making  cuts  and  the 
other  works  spoken  of,  to  increase  its  carrying  capacity  and  thus 
accommodate  the  floods  which  are  passed  through  the  channel  above. 

Cut-offs — Loioer  Sacramento  River. 

Besides  the  points  in  the  division  mentioned  from  Butte  Slough  to 
Feather  River,  the  only  other  locality  where  the  cut-ofF  treatment  is 
admissible  on  the  Sacramento  River,  is  at  the  upper  end  of  Steamboat 
Slough,  where  it  is  desirable  to  open  up  a  new  head  for  that  channel, 
in  the  process  of  making  it  the  principal  line  of  escape  for  the  flood 
waters.  This  subject  is  quite  fully  discussed  in  my  report  to  the  Leg- 
islature, and  I  will  not  say  more  upon  it  until  I  present  the  details 
in  a  special  paper. 

Forcing  the  scouring  ayid  enlargement  of  the  main  rivers. 

Sixth — Works  calculated  to  confine  the  waters  of  the  river  to  its 
channel  and  cause  an  enlargement  thereof  by  the  scouring  action 
thus  brought  about. 

These  works,  of  course,  are  levels,  a  complete  system  of  which,  from 
the  highest  point  on  the  river  where  its  waters  escape  into  the  back 
basins  to  the  point  where  full  tidal  action  is  met  at  the  foot  of  Grand 
Island,  is  essential,  in  my  opinion,  to  success  in  the  work  of  rectifying 
its  channel  and  its  final  maintenance  in  an  efficient  and  serviceable 
condition  as  a  line  of  flood  escape  and  a  navigable  thoroughfare. 

Concentration  of  waters. 

That  the  concentration  and  deepening  of  running  water  does 
increase  its  power  to  transport  sediment,  and  thus  bring  about  an 
enlargement  of  its  channel,  if  the  bed  and  banks  thereof  are  of  a 
character  to  be  at  all  readily  moved,  engineers  and  others  who  study 
such  matters  are  well  agreed. 
2 


10 

The  confining  of  a  greater  body  of  water  over  the  bed  of  the  Sacra- 
mento River  will  undoubtedly  cause  its  enlargement  by  the  process 
referred  to;  and  if  local  obstructions  are  removed  in  the  manner 
heretofore  spoken  of  or  in  any  manner  which  may  be  necessary,  this 
enlargement  will  go  on  so  long  as  the  waters  are  held  in  and  the  bot- 
tom is  found  to  be  of  the  character  known  to  exist  generally  through- 
out the  lower  river,  until  the  stream  is  much  increased  over  its  present 
dimensions;  provided,  that  the  extraordinary  flow  of  sands  by  which 
the  waters  are  now  overloaded  is  checked  in  the  mining  tributaries. 

The  levee  system. 

It  is  frequently  urged  in  argument  against  the  levee  system  of  river 
improvement,  that  the  prevention  of  overflow  causes  the  rapid  eleva- 
tions of  the  stream's  bed  as  compared  to  the  banks  and  back  lands 
upon  which  the  waters  are  prevented  from  spreading  their  sediments, 
and  thus  finally  results  in  the  overthrow  of  the  levees,  destruction  of 
the  lands,  and  injury  to  the  river  itself. 

Although  in  the  course  of  ages  this  result  might,  under  the  natural 
order  of  things,  have  been  brought  about  by  leveeing  the  Sacramento 
River,  it  is  certainly  a  question  of  much  less  time,  under  existing  cir- 
cumstances, when  the  channel  below  the  mouth  of  Feather  River 
will  be  destroyed,  if  the  whole  river  is  not  treated  by  the  levee  system; 
and  as  for  the  back  lands,  they  can  be  no  worse  off"  than  they  are  now 
in  any  event. 

Deterioration  of  the  Sacramento  River. 

This  river  channel  is  being  destroyed  by  the  sands  which  are  rolled 
along  its  bottom,  not  by  the  fine  sediments  which  are  carried  in  sus- 
pension by  its  waters,  and  which  only  would  be  carried  in  large 
quantities  out  of  it  upon  the  back  lands  if  the  levees  were  obliterated. 

The  escape  of  waters  from  the  channel  would  not  relieve  it  from 
the  charge  of  solid  matter  which  it  annually  receives,  but  would 
simply  cause  the  permanent  lodgment  of  that  matter  therein,  whereas, 
by  the  confinement  of  its  waters  alone  can  the  conditions  be  produced 
under  which  this  detritus  may  be  carried  forward  to  the  flats  and 
marshes  of  Suisun  Bay,  where  it  will  do  less  harm,  for  many  years  to 
come,  than  where  it  is  lodging  now. 

We  have  had  the  low-water  plane  of  this  river  raised  two,  three, 
four,  and  even  five  feet  during  the  past  twenty  years.  Such  a  rapid 
change  was  never  heard  of  before  in  the  history  of  other  large  rivers, 
and  where  the  levee  system,  too,  had  equal  scope  for  action.  The  bed 
of  the  Po,  a  river  completely  leveed,  and  whose  waters  are  highly 
charged  with  sediment,  has  not  been  raised  so  much  during  the  period 
of  its  recorded  history.  The  levees  of  the  Po  may  have  caused  a  rela- 
tive rise  of  several  feet  in  its  bed  over  that  of  its  banks  during  the 
past  two  centuries,  and  so  the  levees  of  the  Sacramento  may  ultimately 
have  that  effect.  But  the  first  eff'ect  of  a  complete  levee  system  on 
this  river,  when  it  is  brought  to  a  good  regimen  and  the  flow  of  sands 
stopped,  Avill  be  to  cause  a  great  scouring  out  of  its  bed  and  enlarge- 
ment of  its  channel,  and  thus  lower  both  its  flood  and  Tow  water 
planes,  and  many  years  will  elapse  before  the  eff'ect  of  the  levees  in 
causing  a  contrary  action  will  be  felt. 

The  Mississippi  and  the  Sacraviento. 

A  river  such  as  the  Mississippi,  whose  great  defect  in  capacity  is 


11 

due  to  the  very  shoal  bars  caused  by  caving  banks  and  great  irregu- 
larity of  width,  can  have  its  waterline  sufficiently  lowered  by  the 
simple  scouring  out  of  these  shoals  to  carry  its  floods  between  banks 
without  a  levee  system  as  a  necessary  part  of  the  plan. 

Not  so,  however,  with  the  Sacramento.  We  must  remember  that 
such  is  not  the  principal  cause  of  deficient  capacity  in  our  river.  Its 
banks. are  quite  stable  where  the  cay^acity  is  small;  but  few  shoals 
exist  to  be  removed,  and  these,  although  their  continued  presence 
would  prevent  a  general  improvement  of  the  channel,  are  not  them- 
selves tlie  principal  cause  of  its  inefficiency. 

The  Mississippi  River,  with  a  flood  discharge  of  one  million  two 
hundred  thousand  to  one  million  four  hundred  thousand  cubic  feet 
per  second  due  to  it,  carries  over  or  in  its  main  bed  from  Ave  sixths 
to  nine  tenths  of  its  waters,  losing  one  sixth  to  one  tenth  only  into 
the  swamps  at  high  flood  stage. 

The  Sacramento  River,  between  Butte  Slough  and  the  mouth  of 
Feather  River,  with  a  flood  discharge  of  eighty  thousand  cubic  feet 
per  second  due  to  it,  carries  through  only  thirty  thousand,  having 
lost  into  the  back  basins  on  its  course  nearly  two  thirds  of  its  waters. 
There  is  no  considerable  obstruction  to  flood  flow  from  shoals  in  this 
part  of  the  river.  The  channel  is  narrow,  has  Arm  banks,  and  is 
exceedingly  crooked. 

The  floods  rise  to  their  maximum  height  in  the  upper  portion  of 
this  division  next  below  Butte  Slough,  and  overtop  levees  three  or 
four  feet  in  height  before  the  water  is  bank  high  at  Knight's  Landing 
twenty  or  thirty  miles  below. 

Defects  of  the  Sacramento  River. 

As  before  remarked,  these  divisions  of  the  Sacramento  River — from 
Butte  Slough  to  the  mouth  of  Feather  River — are  in  need  of  some- 
thing more  than  the  sweeping  out  of  shoals.  The  channel  must  be 
straightened  and  heavily  leveed  to  facilitate  and  force  its  enlargement 
throughout. 

This  river  is  naturally  too  small  for  the  amount  of  water  that  is 
presented  to  it  generally  throughout  its  course,  because  for  ages  past 
so  large  a  portion  of  its  volume  at  time  of  flood,  has  from  local  causes 
escaped  into  the  back  basins  that  the  channel  way  has  become  con- 
tracted. The  proof  of  this  action  is  found  in  the  fact  that  below  every 
escape  channel  of  note  all  along  its  course  there  is  a  radical  diminu- 
tion of  average  cross  sectional  area;  and  furthermore,  as  the  water 
has  escaped  gradually  over  the  banks  all  along,  there  is  a  gradual 
diminution  in  width  found  in  going  down  stream  through  each  grand 
division  of  the  river,  from  one  large  outlet  or  tributary  to  the  next 
below,  until  we  arrive  at  the  region  below  Grand  Island,  where  the 
tide  has  full  sway  and  its  flow  regulates,  in  a  great  measure,  the  width 
and  depth. 

The 'po'pular  idea  of  filling  the  low  basins. 

We  have  frequently  heard  that  the  Sacramento  River  should  be 
allowed  to  overflow  its  banks  so  that  the  low  basins  might  become 
fllled  up.  It  may  be  remarked  here,  with  propriety,  that  these  basins 
would  not  fill  up  unless  the  river  deserted  its  present  course  and  occu- 
pied them  in  turn  as  channel  ways.  The  river  bed  and  its  immedi- 
ate banks  were  naturally  built  higher  than  the  basins  before  the 
advance  of  the  sands  from  the  mines,  and  they  would  probably  con- 


12 

tinue  to  rise  more  rapidly  than  the  basins,  for  the  sediments  brought 
down  by  the  waters  of  such  streams  are,  for  the  most  part,  deposited 
immediately  on  the  bank  wdiich  is  naturally  overflowed,  and  it  is 
only  when  the  waters  escape  with  force  tlirough  a  crevasse  that  the 
solid  matter  is  carried  far  back  into  the  basin  and  elevates  it  com- 
mensurate with  the  rate  of  elevation  of  the  river  bank  and  bed. 

The  true  idea  of  this  ynatter. 

Thus  the  only  way  to  equalize  the  land  elevation  back  from  the 
river  to  that  along  its  bank  would  have  been  to  levee  the  river  and 
force  streams  of  water  back  to  the  basin  through  channels,  and  there 
cause  the  deposit  of  their  sediments. 

But  as  the  river  has  received  this  charge  of  sand,  which  cannot 
thus  be  sluiced  out  on  to  the  low  lands,  to  any  great  extent  at  least, 
and  as  the  preservation  of  the  river  is  the  object  in  view  and  not  the 
tilling  up  of  the  basins,  there  is  still  greater  necessity  now  for  a  com- 
plete confinement  of  the  waters  between  levees. 

I  refer  in  the  above  to  the  Sacramento  River  below  the  mouth  of 
the  Feather,  and  presume  that  the  object  is  to  preserve  and  improve 
its  channel.  That  this  river  itself  could  be  turned  into  the  basin 
which  flanks  it  on  the  west,  and  there  be  made  to  deposit  its  sediment 
for  some  years  to  come,  is  quite  certain;  but  the  result  w^ould  be  de- 
struction to  the  present  channel,  and  the  future  would  be  altogether 
problematical  with  the  land  and  cities  below  the  point  of  turning. 

Necessity  for  a  levee  system  on  the  Sacramento  and  Feather  Rivers. 

After  the  other  works  which  have  been  hereinbefore  spoken  of  have 
been  well  taken  in  hand,  the  general  leveeing  of  the  river  should 
begin.  This  work  should  be  prosecuted  from  the  upper  portion  of 
the  stream  downwards,  in  the  reverse  direction  from  that  of  the  other 
principal  improvements.  The  channel  itself  should  be  cleared  of 
local  obstructions  from  the  lower  end  up,  to  bring  about  the  condi- 
tions under  which  it  will  proflt  by  the  effects  of  leveeing  and  conflning 
its  waters  and  then  this  forcing  should  commence  at  the  upper  end. 

The  flrst  leveeing  that  is  undertaken,  therefore,  other  than  that 
necessary  to  equalize  banks  along  the.  river  generally  and  close  gaps 
as  before  explained,  should  be  from  Chico  Creek  to  Butte  Slough. 

In  my  report  to  the  Legislature,  already  referred  to,  will  be  found 
some  general  suggestions  for  the  disposition  of  the  levees  along  this 
part  of  the  river  as  well  as  through  other  divisions.  In  special  reports 
on  the  subject,  hereafter  to  be  submitted,  the  matter  will  be  treated 
more  in  detail. 

OTHER   WORKS. 

I  have  now  classified  the  works  which  it  is  essential  should  be 
carried  forward  for  the  rectification  of  the  main  rivers  of  this  valley, 
and  have  indicated,  in  a  general  way,  the  localities  where  they  are  to 
be  undertaken  and  the  order  of  their  proper  progress. 

In  addition  to  these  it  may  be  necessary,  as  time  goes  on,  to  execute 
other  works,  some  of  them  of  considerable  magnitude,  in  order  to 
relieve  the  large  rivers  of  the  load  of  silt  which  is  brought  to  them 
and  insure  their  continued  improvement,  as  w^ell  as  to  otherwise 
dispose  of  flood  waters,  if  the  drainage  of  the  valley  is  to  be  made 
complete. 


13 

Diversion  of  tributaries  to  deposit  detritus. 

For  instance,  although  the  Sacramento  River  itself  cannot  with 
propriety  and  safety  be  turned  into  any  of  the  low  basins  which  flank 
it,  as  a  means  of  disposing  of  the  sands,  the  case  m^ay  be  different  with 
several  of  its  tributaries,  notably  the  American  and  the  Bear  Kivers, 
which  might  be  led  to  deposit  their  sands  in  the  low  basin  lying  be- 
tween the  two  on  the  east  side  of  the  Sacramento.  Indeed,  they  both 
do  so  now  in  a  degree,  and  during  the  past  season  the  Bear  River  has 
shown  a  strong  disposition  to  turn  to  the  south  altogether  and  desert 
its  former  mouth  into  the  Feather  for  an  outlet  into  the  basin  men- 
tioned. 

An  examination  in  detail  of  the  practicability  and  cost  of  thus  dis- 
posing of  the  sands  of  these  two  troublesome  tributaries  will  be  made 
under  my  direction  during  the  present  season,  and  will  form  the 
subject  of  a  special  report  at  a  later  date. 

Diversion  of  the  Coast  Range  Creek  flood  loaters. 

And  still  again,  the  disposal  of  the  waters  of  Putah  and  Cache 
Creeks,  which  flow  into  the  Yolo  basin,  is  an  essential  part  of  a 
complete  system  of  drainage  for  this  district,  if  not  absolutely  a  neces- 
sary operation  in  the  rectification  of  the  main  river  channels.  This 
project  is  discussed  in  Part  II  of  my  report  to  the  Legislature,  and  I 
invite  your  attention  to  the  view^s  there  advanced. 

In  my  opinion,  these  creek  waters  should  be  turned  through  a  high 
grade  canal  over  the  Montezuma  hills,  to  an  independent  outfall  in 
the  slough  north  of  Suisun  Bay.  By  this  means  only  can  the  great 
accumulation  of  water  in  the  Yolo  iDasin  be  prevented,  the  levees  of 
the  river  be  maintained  and  rendered  efficient  at  reasonable  outlay, 
and  the  success  of  the  drainage  of  the  valley  be  rendered  complete. 

GENERAL  REVIEW  OF  THE  RIVER  TREATMENT  PROPOSED. 

Glancing  over  what  has  been  said  in  this  report,  and  in  that  made 
to  the  Legislature  in  January,  it  will  be  found  that  I  have  advocated 
the  Conservation  treatment  in  the  improvement  of  the  main  rivers 
of  this  valley:  that  I  propose  to  bring  the  channels  to  a  good  regimen 
— even  capacity  to  do  the  duty  required — by  straightening  them  where 
necessary  and  admissible,  by  scouring  out  shoals  where  these  exist, 
particularly  in  the  lower  river,  by  training  the  current  to  destroy 
great  eddies,  and  by  preventing  the  local  escape  of  flood  waters  in 
large  volume,  and  to  supplement  its  present  capacity  by  raising  levees' 
which  will  themselves  form  a  larger  channelway  and  force  the 
enlargement  of  that  already  existing  by  the  scouring  action  of  the 
conflned  waters. 

A  system  of  levees  necessary. 

And  I  hold  that  a  levee  system  is  necessary  to  preserve  the  existing 
channels  of  the  Sacramento  and  Feather  Rivers  and  to  accomplish 
their  rectiflcation. 

If  these  channels  were  more  nearly  proportioned  in  size  to  the 
volume  of  water  which  comes  down  the  valley,  and,  like  many  other 
streams,  were  deflcient  in  capacity  merely  because  of  local  obstruc- 
tions, such  as  extended  bars,  their  rectiflcation  could  be  accomplished 
without  the  levees.     But,  as  has  been  shown,  such  is  not  the  case,  and 


14 

we  can  only  accomplish  the  object  through  the  medium  of  a  levee 
system. 

Could  we  sweep  out  of  existence  all  levees  now  standing  along  the 
Sacramento  and  Feather  Rivers,  the  floods  would  spread  into  the 
back  basins  at  many  places,  and  there,  finding  shorter  lines  of  escape 
from  point  to  point  on  the  rivers,  would  pursue  these  routes,  robbing 
the  channel  in  some  of  its  divisions  of  the  waters  due  to  it  and  nec- 
essary to  preserve  its  size,  and  gorging  the  channel  with  more  than 
it  could  carry  at  other  points. 

The  result  would  be  the  contraction  of  the  existing  channels  in 
some  of  their  divisions  and  the  formation  of  new  outlets  or  the  en- 
largement of  those  already  in  existence,  until,  by  the  action  of  some 
great  flood,  the  channel  of  the  river  itself  would  change  materially. 
This  is  just  what  was  going  on  before  leveeing  commenced  here. 

Now  there  are  levees  over  four  fifths  of  the  route  of  the  river  within 
the  district  where  their  waters  could  naturally  escape  into  the  back 
basins.  These  levees  are  of  very  uneven  height,  and  some  of  them 
badly  located.  If  they  are  left  in  their  i^resent  condition  and  an 
attempt  be  made  to  improve  the  channels,  what  will  be  the  result? 
Manifestly  a  more  unfavorable  one  than  if  there  were  no  levees  at  all. 
The  waters  would  escape  where  the  levees  are  weakest,  or  where  there 
are  none,  and  in  large  volume  locally,  as  they  do  now  in  reality,  and 
the  river  could  not  be  brought  to  a  good  regimen,  for  there  would  be 
no  control  of  the  floods,  which  would  leave  the  channel  or  return  to 
it  wherever  opportunity  offered;  and  without  a  nearly  perfect  regimen 
we  can  hope  for  no  general  improvement  in  the  channel. 

The  object  is  to  prevent  the  further  deterioration  of  these  rivers 
and  to  improve  them. 

The  detritus  lodged  in  the  river  beds  must  be  disposed  of  and  the 
channels  otherwise  rectified  and  enlarged.  It  is  absurd  to  talk  of 
dredging  them  all  out,  as  has  been  publicly  suggested.  Twenty  mil- 
lions of  dollars  would  not  more  than  free  the  two  rivers  by  this 
process. 

A  portion  of  the  sediment  should  be  used  in  levee  construction,  but 
the  great  mass  must  be  swept  out  by  the  river  currents.  This  can 
only  be  accomplished  by  putting  the  rivers  in  condition  to  facilitate 
this  action,  and  by  a  control  of  all  ordinary  floods;  and  a  system  of 
good  strong  levees  is  essential  for  this  treatment. 

Such  a  system  as  is  necessary  for  this  purpose,  however,  will  not 
effect  the  complete  reclamation  of  all  of  the  swamp  lands  in  the  great 
basins  of  the  district,  but  of  course  would  do  much  toward  that  end. 
There  would  still  be  a  necessity  for  organized  action  in  the  reclama- 
tion districts  which  must  continue  to  exist  and  each  labor  in  its  own 
behalf,  while  the  drainage  work  will  be  for  the  common  good  of  all. 
This  subject  is  more  fully  touched  upon  in  a  report  submitted  by  me 
to  the  State  Board  of  Drainage  Commissioners,  under  date  of  the 
twenty-sixth  of  May,  and  to  that  paper  I  ask  your  attention. 

AX   ESTIMATE    OF   COST. 

Concerning  the  probable  cost  of  the  works  herein  outlined,  I  can 
only  at  this  time  give  a  rough  idea.  To  construct  levees  of  proper 
size  entirely  anew  along  the  Feather  and  Sacramento  Rivers  where 
necessary  within  this  district,  would  cost  in  the  neighborhood  of  three 
millions  of  dollars. 


15 

It  may  be  said  that  one  third  of  this  work  has  been  accomplished 
efficiently  thus  far,  so  that  it  could  be  made  a  part  of  the  work  of  the 
future.  We  have  then  a  balance  of  two  millions  of  dollars  to  be 
expended  on  this  class  of  work. 

An  estimate  of  what  miglit  be  expended  to  advantage  within  the 
next  ten  years  may  be  made,  as  follows: 

Levee  work $2,000,000 

Channel  corrections,  etc 2,01)0,000 

Storing  sands 1,000,000 

$5,000,000 

Fully  one  half  of  this  work  is  such  as  the  general  government  might 
possibly  undertake  for  the  preservation  and  improvement  of  the 
rivers  as  navigable  streams,  but  it  must  be  brought  forward  in  its  order 
with  the  other  works,  and  cannot  be  left  behind,  else  the  whole  will 
be  a  failure. 

The  works  should  be  so  carried  on  as  to  diminish  the  time  of  exe- 
cution as  much  as  possible;  there  would  be  economy  in  such  a  course, 
for  they  will  undoubtedly  cost  more  unless  put  in  final  condition  as 
fast  as  natural  action  will  permit. 

Supposing  the  five  millions  of  dollars  were  expended  during  the 
next  ten  years,  I  estimate  that  the  cost  of  maintenance  would  be 
about  two  hundred  thousand  dollars  per  annum  after  that  period, 
half  of  VN'hich  would  be  for  storage  of  sands  and  half  for  river  works; 
and  the  general  government  might  be  expected  to  bear  half  of  the 
expense  if  it  pursues  its  present  policy  in  river  works. 

The  maintenance  of  levees,  while  properly  remaining  under  the 
direction  of  the  Drainage  Districts  Boards,  should  ultimatel}^  be  paid 
for  by  the  lands  thus  protected  from  inundation,  and  thus  the  State's 
share  of  the  expense  of  maintaining  her  rivers  in  good  condition  will, 
in  the  future,  be  reduced  to  a  small  amount. 

Very  respectfully  submitted. 

WM.  H.  HALL, 

State  Engineer. 


DAMS  FOR  IMPOUNDING  MINING  DETRITUS. 


REPORT    ON    DAMS 


STORAGE  OF  MINING  DETRITUS 


ON  THE  YUBA  AND  BEAR  RIVERS. 


Office  of  the  State  Engineer,  | 

Sacramento,  July  6th,  1880.  J 

To  the  Board  of  Directors  of  Drainage  District  No.  1,  Sacramento,  Cal. 

Gentlemen:  In  the  matter  of  constructing  dams  for  storing  mining 
detritus  on  the  Yuba  and  Bear  Rivers,  I  have  to  report  now  in  gene- 
ral terms,  and  when  further  examinations  shall  have  been  made  of 
the  several  sites  for  dams  and  storage  ground,  I  will  submit  another 
report  concerning  the  same,  and  recommend  the  adoption  of  a  definite 
policy  on  each  river. 

Transportation  of  sediment  hy  vioving  waters. 

The  conditions  in  a  stream  most  favorable  to  the  transportation  of 
sediments  by  its  waters  are  :  (1),  that  it  be  deep  in  proportion  to  its 
width ;  (2),  that  it  be  of  uniform  width  and  grade;  (3),  that  its  channel 
be  of  good  alignment,  free  from  sudden  bends,  and  (4),  that  the  lines 
of  its  currents  be  not  broken  up  by  obstructions  of  any  kind. 

With  such  conditions,  a  rapid  current,  uniform  in  its  movement 
throughout  the  several  succeeding  reaches  and  divisions  of  the  stream, 
with  a  sharply  inclined  vertical  velocity  curve,  would  be  produced, 
and  the  waters  would  have  great  power  to  transport  solid  matter. 

Reversing  these  conditions  in  any  manner,  the  waters  drop  their 
silicious  or  earthy  load  in  a  degree  proportional  to  the  extent  of  the 
reverse  order  produced.  Thus,  sediment-carrying  currents  may  be 
made  to  deposit  their  sand  and  slimes  by  checking  the  velocity,  and 
otherwise  destroying  the  conditions  essential  to  their  transporting 
power. 

This  may  be  effected  in  either  one  of  three  ways :  (1),  increasing 
the  width  of  the  stream,  thus  reducing  its  depth  as  a  direct  conse- 
quence, and  indirectly  reducing  it  also  by  causing  the  raising  of  its 
bed  by  deposits  thereon;  (2),  reducing  the  grade  or  slope  of  the  stream 
by  changing  its  alignment,  or  by  raising  its  bed  at  some  point  by  a 
dam;  (3),  breaking  up  the  threads  of  its  current  by  the  introduction 
of  pervious  or  partial  obstructions  to  its  flow. 


20 

The  Yuba  and  Bear  River  deposits. 

The  Yuba  and  Bear  Rivers  have  made  immense  deposits  of  gravel, 
sand  and  slime  above  their  confluence  with  the  Feather,  because  their 
grades  greatly  diminish  as  they  approach  that  stream,  their  waters 
have  overtopped  the  low  banks  and  spread  in  wide  sheets  over  the 
adjacent  bottom  lands,  and  the  dense  growth  of  small  timber  and 
brushwood  through  which  they  were  made  to  run  broke  up  the  lines 
of  their  currents. 

Deposits  in  this  manner  occasioned  at  lower  points,  have  served  to 
reduce  the  grade  for  other  points  above,  and  thus,  there  also,  rilling 
has  taken  place;  and  still  again,  in  the  canons  the  natural  irregularity 
of  regimen,  and  the  damming  up  occasioned  by  the  low^er  mining 
dumps,  have  made  many  extended  reaches  the  storehouses  qf  heavier 
detritus. 

Proposed  artificial  deposit  qf  detritus. 

Now^  it  is  proposed  to  cause  an  increased  deposit  from  the  w^aters  of 
these  streams,  at  such  points  that  it  will  not  damage  private  property 
or  injure  the  navigable  main  drains  below. 

So  far  as  the  channels  of  the  Yuba  and  Bear  Rivers  themselves  are 
concerned,  it  matters  not  whether  they  are  either  restored  or  supple- 
mented by  other  deep  ones,  so  long  as  the  objects  just  expressed  are 
attained.  Indeed,  the  primary  object  being  to  preserve  and  improve 
the  channels  of  the  main  drains  or  navigable  streams — the  Sacra- 
mento and  Feather  Rivers— it  would  seem  to  be  advisable  to  avoid 
any  immediate  restoration  of  the  channels  of  the  tributaries;  for  ma- 
terials washed  from  them  must  pass  down  into  these  larger  rivers, 
and  it  is  important  to  withhold  all  the  sands  that  can  possibly  be  held 
back,  at  least  until  such  time  as  they — the  rivers  below — can  have 
been  brought  to  a  good  regimen  and  scoured  out. 

In  view  of  this  condition,  I  recommend  that  the  treatment  for  the 
Yuba  and  the  Bear  be  such  as  to  retain  their  channels,  for  years  to 
come,  at  least,  somewhat  as  they  now  are,  in  wide  and  shallow  beds; 
and  rather  encourage  further  deposit  upon  the  sand  wastes  already 
formed  (where  this  can  be  done  without  great  damage  to  other  yet 
uninjured  property),  than  to  cause  the  restoration  of  any  deep  chan- 
nels through  these  deposits. 

This  treatment  should  be  pursued  until  such  time  as  it  shall  have 
been  shown  that  the  sands  are  stopped  at  higher  points,  and  the  large 
rivers  below  are,  in  a  great  measure,  relieved  from  their  filling. 

Locations  for  and  character  qf  dams. 

Within  the  canons  of  the  mountains  through  which  the  Bear  and 
Yuba  flow,  it  is  not  possible  by  any  direct  method  to  widen  the  chan- 
nels. This  can  only  be  accomplished  by  building  up  their  beds 
through  the  action  of  dams,  thus  eff'ecting  the  double  object  of 
increased  width  and  decreased  grade  above  each  dam. 

The  subject  of  retaining  the  detritus  by  means  of  stone  dams  within 
the  canons  of  the  Yuba  River  w^as  discussed  by  me  in  Part  III  of  the 
report  to  the  Legislature,  submitted  in  January,  and  allusion  was 
made  to  the  possibility  of  eff'ecting  the  same  end  by  means  of  dams 
of  brush  and  gravel  at.  lower  points  on  the  same  streams. 

Further  observation  and  thought  have  convinced  me  that  the  work 
should  be  commenced  as  low  down  on  the  streams  as  the  detritus  can 


21  • 

be  held  safely,  and  that  tlie  dams  built  must  at  first  be  of  the  latter 
mentioned  class. 

•  The  sands  stored  at  lower  points  will  themselves  serve,  to  some 
extent,  as  dams  for  storage  sites  at  points  above;  and  furthermore, 
brushwood  is  the  only  material  to  be  had  at  some  of  the  sites  for 
dams,  and  these  structures  must  be  built  of  it  if  at  all. 

A  brush  dam  possesses  the  advantages  of  greater  stability  and  safety 
on  soft  or  sandy  foundations,  and  great  cheapness  of  construction. 

A  rock  dam  has  in  its  favor  the  considerable  advantage  of  the  dura- 
bility of  its  material  and  of  stability  under  great  floods — supposing, 
of  course,  its  foundation  to  be  secure. 

•  Upon  the  wide  sand  fiats  below  the  canons  proper,  undoubtedly 
brush  dams  should  be  adopted,  primarily,  at  least;  while  between  the 
high  banks  of  the  foot-hills,  rock  dams,  where  material  is  abundant, 
can  be  most  conveniently  built,  and  would  have  the  advantage  of 
permanence  to  a  degree  which  should  render  their  ultimate  adoption 
advisable. 

storage  heloio  the  canons. 

Were  the  sands  stopped  at  the  canon  mouths  on  the  Yuba  and  Bear, 
it  would  still  be  necessary  in  preventing  the  channeling  out  ^t  lower 
points  through  the  sand  wastes  above  the  Feather,  to  lay  in  some  low 
brush  dams  or  sills,  as  heretofore  alluded  to,  in  order  that  these  lower 
sands  might  not  be  swept  down  before  the  large  rivers  could  receive 
them  safely.  This  being  the  case,  it  will  be  wise  to  make  these  ob- 
structions do  the  additional  duty  of  holding  more  sands  if  possible, 
and  hence  at  the  lowest  point  where  this  can  be' done  with  safety  the 
first  dams  should  be  built. 

All  of  the  sands  which  w^ill  come  down  these  streams  for  several 
years  can  be  thus  stored  below  the  canons  proper,  on  lands  already 
covered;  and,  by  an  extension  of  leveeing  work,  still  greater  storage 
capacity  can  be  obtained  over  the  same  superfices. 

stone  dams  commenced  with  brush. 

The  great  danger  of  destruction  to  a  stone  dam  of  the  character  and 
for  the  purposes  it  is  proposed  to  build  them  oji  these  streams,  is  from 
undercutting  at  its  down  stream  edge,  and  in  building  of  stone  alone 
it  is  difficult  and  expensive  to  guard  against  this  action. 

With  brush,  however,  this  difficulty  is  much  more  readily  met,  and 
it  is  proposed  to  protect  the  stone  dams  by  submerged  brush  dams  at 
the  down  stream  edges  of  their  aprons.  These  brush  dams,  by  rais- 
ing them  higher,  can  be  made  to  retain  a  large  amount  of  sand  above 
them  before  the  stone  dam  is  commenced,  and  hence,  again,  we  have 
sound  arguments  not  only  for  the  construction  of  the  hrst  dams  low 
down  on  the  streams,  of  brush,  but  for  the  commencement  of  all  dams 
with  that  material. 

THE    STONE    DAMS    PROPOSED. 

It  may  be  well  to  consider  here  for  a  moment  the  principles  upon, 
which  we  are  to  proceed  in  the  matter  of  constructing  dams,  both  of 
brush  and  of  stone. 

Stone  dams— character  of. 

The  proposed  stone  dams  would  be  massive  structures  of  loose 


»  22 

rubble,  not  coursed  or  hand-laid,  but  somewhat  assorted  with  respect 
to  size  of  pieces,  as  hereinafter  explained,  with  crests  ten  to  twenty- 
tive  feet  in  thickness,  and  long  slopes  both  up  and  down  stream. 

For  a  clear  idea  of  the  problem  of  these  stone  dams,  it  is  essential 
to  remember  that  they  are  to  be  for  the  purpose  of  storing  sands  and 
not  water:  and  that  it  will  not  be  necessary,  under  a  proper  system,  to 
have  any  one  of  them  more  than  twenty  feet — say  an  average  of  twelve 
feet — in  height  at  any  time  over  the  bottom  immediately  up  stream 
from  it.  Hence  the  dam  becomes  but  a  facing  for  an  upper  plane  of 
sand;  it  becomes  filled  and  impermeable  only  by  degrees  as  the  sands 
rise  upon  it,  and  the  hydrostatic  pressure  behind  it  is  always  limited 
to  that  due  to  but  a  few  feet  in  depth  of  water. 

Such  a  dam  is  intended  to  be  added  to  each  year,  using  the  filling 
above  as  a  foundation  for  a  portion  of  each  addition,  until  the  struc- 
ture is  brought  to  the  desired  height  for  its  site,  and  becomes  solidified 
with  the  tilling  against  it. 

Stone  dams — their  loeak  points. 

If  rocks  of  sufficient  size  are  used  its  destruction  could  only  be 
accomplished  :  (1),  by  the  water  finding  a  low  place  in  the  crest  and 
there  concentrating  its  force;  (2),  by  undermining,  or  (3),  by  flanking 
its  ends. 

The  mere  pressure  of  water  or  shock  of  a  flood  could  not  overthrow 
a  dam  of  this  kind,  so  that  its  destruction,  if  ever  accomplished,  could 
only  be  gradual,  and  not  a  sudden  catastrophe. 

Ordinary  care  in  construction  and  maintenance,  and  the  use  of 
very  large  stone  on  the  crests  and  down  stream  faces,  would  prevent 
damage  from  channelling  down  and  concentration  of  waters  at  any 
point. 

Ordinary  good  construction,  too,  will  insure  against  the  ends  being 
flanked  by  the  floods — for  the  water  may  be  kept  away  from  the 
extreme  ends  of  the  crest,  and  a  good  junction  may  be  made  with  the 
bed  rock  in  the  faces  of  the  hills. 

On  the  foundation  we  have  the  weakest  line  to  guard. 

If  large  rocks,  say  twenty  tons  apiece,  be  laid  in  a  row  on  the  sands- 
across  the  bed  of  a  river,  such  as  the  Yuba  or  the  Bear,  they  will 
quickly  disappear — the  sands  from  between  them  will  scour  out,  the 
rocks  will  gradually  drop  into  the  cavities  produced,  and  will  soon 
have  disappeared  almost  entirely,  if  not  quite. 

If  the  same  quantity  of  stone,  broken  to  the  size  of  ordinary  river 
gravel,  be  placed  in  a  ridge  across  the  channel  in  a  similar  locality  it 
will  not  be  undermined;  the  top  stones  will  be  swept  off,  probably, 
one  by  one  by  the  force  of  the  current,  and  the  whole  ridge  flattened 
down,  in  time  possibly  destroyed  by  this  means,  but  it  will  not  be 
dropped  out  of  sight  in  the  sands  by  the  action  of  the  current  passing 
under  it  from  above.  If  there  should  be  considerable  fall  over  it  and 
no  apron  or  fiat  surface  of  stones  below,  the  sands  would  probably  be 
swept  away  from  its  down  stream  edge,  and  the  stones  or  gravel  would 
be  washed  into  the  cavity  thus  formed. 

Here  we  have  a  picture  of  the  manner  in  which  a  rubble  stone  dam 
may  be  undermined,  either  by  the  water  running  along  upon  the 
sands  by  way  of  the  spaces  between  the  stones  that  compose  the 
structure,  from  above,  or  by  the  cutting  under  the  lower  edge  of" 
the  structure  after  having  passed  over  its  crest. 


23 

stone  dmns  for  storing  detritus — principles  to  he  observed. 

Should  we  imagine  a  dam  built  up  in  thin  layers,  the  material  in 
each  succeeding  one  graded  in  size  somewhat  larger  than  in  the  layer 
below — from  the  dimension  of  the  particles  of  sand  up  to  those  of  the 
great  mass  of  rock  capable  of  withstanding  any  force  of  water  that 
can  possibly  be  brought  to  bear  upon  it — we  would  have  before  us  a 
dam  totally  incapable  of  destruction  by  undermining  from  above, 
because  the  interstices  between  the  particles  of  no  one  layer  would  be 
sufficiently  great  to  admit  the  passage  of  a  stream  of  water  strong 
enough  to  wash  out  its  particles  or  those  in  the  layer  next  below. 

In  the  construction  of  stone  dams  to  store  the  detritus  on  the  Yuba 
and  Bear  Rivers  we  must  approach  this  condition  in  their  parts  ;  the 
sands  under  the  foundation  must  be  covered  so  that  the  waters  of  per- 
colation will  not  wash  them ;  the  rocks  upon  the  crests  must  be  of 
such  great  dimensions  that  the  force  of  the  water  cannot  move  them, 
and  the  pieces  of  the  intervening  material  must  be  intermediate  in 
size. 

Practical  construction  of  stone  dams. 

The  foundation  may  be  secured  by  first  depositing  layers  of  very 
fine  stone  upon  which  to  build  ;  or  the  same  object  may  be  attained 
by  building  the  stone  dam  upon  a  foundation  mattrass  or  matting  of 
small  brush,  with  fine  stone  or  gravel  intermixed. 

Having  secured  the  foundation  from  washing  from  above,  the 
undercutting  at  the  toe  must  be  guarded  against. 

First  of  all,  for  a  considerable  width  below  any  overfall,  there  must 
be  an  apron  to  receive  the  shock  of  the  waters  and  permit  of  their 
taking  a  horizontal  direction  in  the  onward  flow,  before  reaching  the 
movable  bottom. 

This  apron,  of  course,  would  be  most  durable  if  constructed  of 
stone,  provided  its  undermining  were  guarded  against,  and  to  a  stone 
dam  there  should  be  a  stone  apron,  though  one  of  logs  or  of  brush 
and  gravel  might  be  used  safely  for  years. 

The  lower  edge  of  such  an  apron,  of  whatever  material  composed, 
unless  it  were  of  very  great  width  and  the  water  spread  over  it  in  a 
very  thin  sheet,  would  be  liable  to  sufl'er  from  this  undercutting 
influence,  unless  the  transporting  power  of  the  water  were  broken  up 
at  that  point! 

Flowing  over  or  past  a  hard  and  fast  line,  such  as  fhe  edges  of  a 
stone  or  log  apron  would  be,  water  almost  always  attacks  the  soft 
material  adjacent  to  it,  and  cuts  a  hole  or  pit.  On  the  contrary,  a 
windrow  or  driftrow  of  brush,  lodged  in  a  current  so  that  the  waters 
partially  pass  between  the  branches,  causes  a  deposit  of  sediment  and 
the  formation  of  a  bar  below,  which  works  up  to  and  finally  covers 
in  the  brush  itself. 

By  a  proper  construction  and  the  use  of  brush  on  this  principle, 
with  which  to  finish  the  lower  edge  of  the  stone  aprons,  not  only  may 
their  undercutting  be  prevented,  but  the  sands  may  be  caused  to  pile 
up  where  it  might  be  supposed  they  would  cut  out. 

I  do  not  propose  to  consume  time  and  space  in  citing  instances 
where  like  effects  have  been  artificially  produced  in  engineering 
work.  Suffice  it  to  saj^,  that  the  annals  of  modern  river  engineering 
afl'ord  analogous  examples,  and  the  working  of  the  law  upon  which 
the  result  rests  may  be  observed  in  nature  every  day,  and  in  many 
places  upon  our  own  streams. 


24 

I  am  of  the  opinion,  therefore,  that  stone  dams  of  this  character 
can  be  put  upon  the  sand  foundations  in  the  lower  portions  of  and  at 
the  mouths  of  the  canons  of  the  Yuba  and  Bear  Rivers  with  perfect 
safet}'. 

Dams  for  storing  detritus,  and  other  stone  dams. 

I  remark  the  difference  in  principle  upon  which  we  should  proceed 
in  laying  in  the  stone  dams  here  contemplated,  from  that  followed  in 
placing  stone  foundations  for  other  purposes. 

In  the  case  of  the  proposed  rubble  dams  we  expect  percolation 
through  them,  and  only  guard  against  the  washing  out  of  the  mate- 
rial below  by  covering  it  in  with  other  material,  the  nature  or  arrange- 
ment of  which  will  not  admit  of  the  washing. 

We  have  water  highly  charged  with  silt,  which  it  is  expected  will 
deposit  its  load  in  the  dam  as  the  sands  are  rolled  against  it.  We  are 
not  constructing  to  hold  clear  water  or  to  bear  a  heavy  load. 

In  stone  foundations  for  a  bridge  or  a  masonry  dam  the  work  itself 
is  intended  to  be  impermeable  and  immovable  from  the  commence- 
ment ;  the  largest  stones  may  be  placed  at  the  bottom,  and  it  is  not 
intended  that  they  should  move. 

In  the  case  of  the  proposed  rubble  dams,  although  they  must  be 
placed  on  good  sand  and  gravel  foundations,  and  not  on  quicksand 
or  "slickens,"  settlements  which  would  be  utterly  destructive  to 
works  of  the  other  class,  would  not  be  a  serious  circumstance,  indeed 
they  are  to  be  expected,  and  the  dam's  crest  must  be  brought  up  to 
grade  as  well  as  raised,  perhaps,  to  accomplish  more  storage  each 
year. 

stone,  the  2'>ro}yer  material  for  the  future;  brush,  for  the  present. 

And,  in  view  of  the  fact  that  all  dams  to  be  used  in  storing  this 
material  should  be  as  permanent  as  possible,  I  think  the  great  mass 
of  it  in  the  future  should  be  stored  above  stone  works. 

But,  considering  what  has  preceded  in  this  paper,  I  am  clearly  of 
the  opinion  that  the  work  should  be  commenced  with  brush  struc- 
tures, and  possibly  this  brush  work  can  be  used  in  other  ways  so  as 
greatly  to  cheapen  the  stone  structures,  as  hereafter  suggested. 

THE   BRUSH   DAMS   PROPOSED. 

Concerning  brush  dams  there  is  not  so  much  to  say.  The  illustra- 
tion heretofore  cited  of  a  driftrow  of  brush  lodged  in  a  current  affords 
the  idea  of  the  simplest  form  of  such  a  work,  and  the  natural  growth 
of  brushwood  and  small  timber  over  the  sand  flats  in  Yuba  River 
and  Bear  River  presents  another  excellent  example  of  a  pervious 
brush  dam,  which  causes  a  deposit  commencing  below  it,  by  break- 
ing up  the  lines  of  the  current,  and  thus  destroying  its  capacity  to 
transport  its  load  of  solid  matter. 

Natural  brush  dams. 

One  cannot  long  study  the  action  of  this  growth  in  the  localities 
mentioned,  without  being  thoroughly  convinced  of  the  efhciency  of 
the  brush  dams  which  nature  thus  rears  in  the  way  of  the  floods  with 
their  charges  of  sand. 

It  has  only  to  be  seen  for  the  fact  to  be  appreciated,  that  but  a  small 
proportion  of  the  solid  matter  is  carried  through  such  an  obstruction, 


25 

and  that  it  would  only  be  necessaiy  to  close  the  channels  intervening 
between  the  great  growths  of  young  trees,  by  similar  obstructions,  to 
cause  an  almost  complete  interce})ting  of  the  detritus. 

Thus,  were  the  sand-covered  flats  of  the  Yuba  and  Bear  Rivers 
flanked  by  higli  plains  or  levees,  they  might  be  made  to  retain  the 
sediment  to  be  brought  down  for  4  number  of  years  to  come,  by  sim- 
ply causing  the  sands  to  rest  upon  them  on  greater  grades,  by  placing 
low  permeable  brush  dams  at  short  intervals  of  space  in  the  way  of 
the  currents,  and  adding  to  them  from  year  to  year. 

As  it  is,  however,  no  such  banks  exist  very  far  down  into  the  plain; 
the  time  has  passed  when  this  action  could  have  been  availed  of  to 
any  great  extent  without  artiflcially  conflning  the  waters  on  the  sides, 
and  for  this  purpose  very  large  levees  must  be  now  constructed, 
although  by  such  means  the  storage  room  below  the  foot-hills  will  be 
increased,  yet  it  is  limited,  and  we  must  look  forward  to  the  time 
when  it  will  be  exhausted.  When  we  can  no  longer  raise  the  lower 
portion  of  the  storage  ground  there  will  be  an  overfall  necessary  at 
some  point — the  lowest  limit  of  the  deep  storage — and  for  that  a  per- 
vious brush  dam  will  not  sufhce. 

There  must  be  a  Arm  structure  down  whose  face  water  may. fall,  as 
over  a  stone  dam.  without  washing  out  any  of  the  material  in  or 
under  it. 

Impervious  brush  dams 

Of  gravel  and  brush  or  small  trees,  such  a  dam  can  be  readily  built 
to  a  moderate  height. 

The  main  structure,  in  order  that  it  may  be  firmly  held  to  the  sand 
and  gravel,  must  be  built  with  the  tops  of  the  trees  up  stream  with 
their  branches  covered  in  and  incorporated  with  gravel  or  coarse 
sand,  by  which  arrangement  also  the  butt  ends  are  placed  down 
stream  and  form  the  overfall  face  and  crest  of  the  dam. 

An  heavy  apron,  immediately  below  the  overfall,  should  be  con- 
structed in  similar  manner;  while  to  prevent  the  undercutting  action 
from  below,  a  lower  apron  must  be  provided  with  the  brushy  ends  of 
the  trees  down  stream. 

We  would  thus  have,  a  dam  as 'immovable  as  a  drift  tree  which 
lodges  upon  a  sand  bank  and  forever  forms  a  snag,  unless  removed 
by  human  agency. 

stability  of  brush  dams. 

If  we  consider  the  w^dth  to  which  the  waters  of  the  streams  now 
under  discussion  are  spread  at  the  points  where  it  is  proposed  to  con- 
struct brush  dams,  we  will  realize  how  they  will  be  robbed  of  their 
destructive  force  by  being  led  to  encounter  an  obstacle  such  as  a  dam 
in  the  face  of  the  entire  front  of  their  flow. 

For  instance,  the  extreme  flood  discharge  of  the  Yuba  River  is 
about  fifty  thousand  cubic  feet  per  second,  and  its  ordinary  flood  dis- 
charge does  not  exceed  half  that  amount,  while  its  usual  discharge 
through  the  winter  and  spring  is  about  five  thousand  cubic  feet  per 
second. 

I  take  the  larger  figure  to  illustrate  the  case:  At  the  De  Guerre 
dam  site,  the  shortest  proposed  line  of  construction  for  a  brush  dam, 
the  overfall  will  be  about  five  thousand  feet  in  length.  Fifty  thou- 
sand cubic  feet  of  water  per  second,  running  at  a  speed  of  ten  feet  per 
4 


26 

second,  will  pass  over  a  crest  five  thousand  feet  long  in  a  sheet  one 
foot  deep,  or  running  at  the  rate  of  five  feet  per  second,  it  would  pass 
over  the  five  thousand  foot  crest  two  feet  in  depth. 

In  actual  practice  it  would  run  at  a  rate  according  to  its  velocity  of 
approach  to  the  dam,  which  would  make  it  from  1.3  to  1.7  feet  deep 
over  it. 

With  a  stick  to  brace  himself,  a  man  could  almost  wade  across  the 
Yuba  River  on  the  crest  of  such  a  dam  at  the  time  of  its  greatest  dis- 
charge, and  could  certainly  do  so  at  time  of  ordinary  flood,  provided 
the  dam  was  so  placed  and  constructed  that  the  water  approached  it 
with  nearly  equal  velocity  at  all  points. 

Now,  a  sheet  of  water  a  foot  and  a  half  deep,  moving  at  the  rate  of 
seven  feet  per  second,  represents  about  the  maximum  moving  force 
we  have  to  contend  against,  and  under  such  circumstances  it  will  not 
be  a  difflcult  task  to  construct  brush  aprons  below  the  dam,  and  so 
guard  them  as  to  insure  against  undermining. 

We  have  examples  of  brush  dams  of  comparatively  slight  construc- 
tion in  California  which  have  long  withstood  the  action  of  water 
running  over  them  to  an  equal,  if  not  a  greater  depth. 

Governing  the  deposit  of  detritus. 

There  can  be  no  doubt  but  that  the  gravel,  sand,  and  much  of  the 
finer  sediment  brought  down  by  these  rivers  can  be  deposited  almost 
wherever  it  is  desired  to  place  them  within  the  territory  now  covered 
by  the  sediments,  and  held  there  permanently  by  brush  work  only, 
to  a  height  varying  from  one  to  twenty  feet,  in  addition  to  the  depth 
of  detritus  already  in  place. 

The  practical  limit  to  thus  disposing  of  this  sand  will  be  found  in 
the  leveeing  to  prevent  the  overflow  of  adjacent  lands. 

Recent  river  works  have  shown  in  a  wonderful  degree  what  com- 
plete control  the  engineer  may  have  over  the  currents  and  their  sedi- 
ments, if  he  only  study  his  subjects  closel}^  and  seize  upon  local 
advantages. 

We  all  know  that  a  lattice  fence  forms  a  complete  wund  break. 
Sands  blown  up  from  the  beach  are  arrested  and  made  to  pile  up  in 
great  dunes  or  ridges  parallel  to  the  water  front  by  the  construction 
of  light  wicker  work  or  brush  fences. 

Works  of  this  kind  are  numerous  in  older  countries,  and  the  experi- 
ment was  successfully  carried  on  for  several  seasons  under  my  direc- 
tion at  the  seaward  end  of  Golden  Gate  Park  in  San  Francisco. 

Similar  constructions  which  do  not  jjresent  enough  resistance  to 
the  currents  of  water  to  be  swept  away  or  undermined  by  them  are 
now  used  to  gradually  check  their  velocity  and  to  force  them  to  drop 
their  sands— like  those  blown  by  the  winds  from  the  beach — where 
the  engineer  desires  to  have  them  rest. 

Within  the  last  two  years,  upon  the  Missouri  River,  near  Omaha,  a 
greater  advance  has  been  made  in  this  class  of  work  than  previously 
chronicled  to  my  knowledge. 

I  here  quote  from  a  popular  account  of  these  operations  recently 
published  in  the  Scientific  American,  deferring  more  extended  notice 
of  the  official  report  spoken  of,  and  the  details  of  works,  until  I  submit 
to  you  a  special  report  on  the  improvement  of  the  larger  streams  in 
your  district. 


27 

Experience  on  the  Misf^ouri  River. 

Speaking  of  the  Missouri  River,  the  journal,  after  describing  the 
action  of  the  stream  at  certain  points,  says : 

"To  keep  the  river  within  re,2;ular  bounds  the  yielding  banks  have  to  be  protected,  the 
velocity  of  the  current  diminished  in  certain  places,  and  the  channel  iield  in  place  by  building 
up  or  solidifying  its  sides.  The  different  means  employed  in  this  sort  of  work  are  described  by 
Captain  Hanbury.  of  the  Engineer  Corps,  in  a  recent  report  upon  the  condition  of  the  Missouri 
River,  near  Omaha.  For  causing  deposits  to  take  place,  and  for  deflecting  the  currents  in 
localities  that  are  to  be  built  out,  floating  brush  obstructions  have  been  ai)plied  with  marked 
success.  The  most  successful  of  these  is  the  floating  brush  dike,  made  by  taking  saplings  from 
twenty  to  thirty  feet  long,  and  from  four  to  six  or  eight  inches  in  diameter,  and  nailing  or 
fastening  to  them  with  wire,  scraggy  brush  of  any  kind  obtainable  in  the  locality.  This  forms 
wliat  is  known  as  the  'weed.'  Instead  of  the  saplings  rope  may  be  used  to  hold  the  brush.  To 
one  end  of  this  '  weed'  is  attached  an  anchor  of  sufficient  weight  to  hold  it  in  position  against 
the  current;  to  the  other  a  buoy  to  hold  up  the  down  stream  end  and  prevent  it  from  going  to 
the  bottom  under  the  pressure  of  the  current  against  it.  These  'weeds'  are  placed  from  ten  to 
twenty  feet  apart,  thus  forming,  the  floating  dike.  Their  action  is  to  check  the  current 
gradually,  without  producing  that  scouring  effect  to  which  the  solid  dike  gives  rise.  This  done, 
a  portion  of  the  material  which  is  rolling  along  the  bottom  or  being  carried  down  in  suspension 
is  dejwsited,  and  causes  a  rise  in  the  bed  of  the  river,  which  changes  its  channel  to  the  direction 
desired.  The  rapidity  with  which  these  deposits  take  place  is  truly  wonderful.  One  season  is 
often  sufflcient  to  raise  the  river  bed  vip  to  the  liinits  of  ordinary  high  water. 

'•  Another  foVm  of  obstruction  that  has  been  tried  with  success  is  the  willow  curtain.  This, 
as  its  name  indicates,  is  made  of  willows  about  an  inch  in  diameter  or  larger,  fastened  parallel 
with  each  other,  and  from  six  to  eight  inches  apart,  by  means  of  wire.  The  curtains  can  be 
made  of  any  desired  width  and  length.  They  are  anchored  in  position  by  weights  attached  at 
intervals  along  the  lower  edge,  and  held  in  an  upright  or  inclined  position  in  the  water  by 
floats  made  fast  to  the  upper  edge.     Their  action  is  similar  to  that  of  the  '  weeds.' 

"■Another  form  that  has  been  experimented  with,  and  which  bids  fair  to  give  good  results,  is  a 
screen  made  totally  of  wire,  something  after  the  fashion  of  a  seine.  It  is  anchored  and  buoyed 
like  the  willow  curtain.  The  rootlets  and  small  vegetable  fibers  that  float  in  large  quantities  in 
the  water  accumulate  upon  the  wires,  and  form  obstructions  sufficient^to  check  the  velocity  of 
the  current." 

Application  of  the  above  experience. 

Here  we  find  remarkably  favorable  results  produced  in  a  deep  and 
rapid  river,  by  methods  the  most  economical  and  safe  in  their  appli- 
cation. It  only  requires  an  intelligent  study  of  our  circumstances 
here  to  apply  some  one  of  these  contrivances  successfully  in  each 
case. 

For  instance,  I  do  not  doubt  that  the  Yuba  River,  now  coursing 
down  the  lin^  of  the  North  levee,  for  about  three  miles  of  its  length, 
transporting  a  great  vojume  of  sediment  past  it  daily,  can  be  made  to 
deposit  this  load  where  it  now  threatens  erosion,  by  the  use  of  some 
such  means  as  the  brush  curtain  applied  on  the  Missouri  River. 
Thus,  by  checking  the  current  at  short  intervals  by  these  screens,  we 
would  build  up  a  levee  strong  enough  to  resist  all  attacks  of  the 
floods — for  there  is  no  reason  why  it  should  not  be  a  thousand  feet 
through  on  the  base — all  deposited  by  the  water  itself  up  to  the 
height  of  the  flood  line. 

These  screens  are  really  open  work  brush  dams,  and  act  as  has  been 
described  before  of  such  works. 

There  are  circumstances,  then,  under  which  pervious  brush  dams 
may  be  used  to  advantage  on  the  Yuba  and  Bear  Rivers,  but  to  store 
the  great  mass  of  sands  that  are  to  come  down  these  rivers,  even 
during  the  flrst  few  years  of  this  work,  more  substantial  structures 
will  be  required  of  brush  and  gravel,  and  in  the  future  the  great  mass 
of  detritus  must  be  held  by  rock  dams  between  the  foot-hills  as  before 
described;  unless,  indeed,  it  is  proposed  to  let  these  sands  spread  over 
large  areas  of  land  as  yet  uninjured. 

And  here  I  remark  that  the  application  of  this  idea  of  causing  the 


28 

waters  to  deposit  their  burden  of  detritus  by  opposing  at  short  inter- 
vals permeable  obstructions  to  their  flow,  is  aliuost  illimitable. 

By  the  use  of  heavy  brush  curtains  trailing  in  the  waters,  and 
swung  from  shore  to  shore  in  the  wider  parts  of  the  river  canons  by 
means  of  cables,  it  would  be  possible  to  arrest  the  great  mass  of  sands 
between  a  series  of  low  rock  and  brush  rapids,  and  thus  All  up  the 
whole  canon  for  a  number  of  miles  in  length  at  once,  without  the  use 
of  any  heav}'  dams  at  all. 

The  cost  of  the  work  would  probabh^  be  excessive,  however,  and 
the  plan  is  only  mentioned  to  show  to  what  extent  the  possibilities 
in  this  matter  reach.  It  is  evident  that  sediment  bearing  waters  may 
be  made  to  deposit  their  load  under  any  ordinary  circumstances;  but 
it  is  also  clear  that  if  the  waters  are  to  continue  to  run  over  the 
deposit,  some  more  stable  obstructions  must  be  introduced  to  prevent 
subsequent  erosion.  Hence  the  introduction  of  the  rock  and  brush 
riflies  spoken  of  above. 

Our  work  not  an  experiment  in  the  popular  sense. 

It  is  well  in  this  connection,  also,  to  allude  to  one  more  point.  It 
has  been  said  that  this  work  is  altogether  experimental.  This  asser- 
tion is  not  correct. 

Nothing  is  more  certain  than  that  the  flow  of  these  sands  can  be 
arrested  before  they  reach  the  main  rivers ;  the  engineering  prin- 
ciples upon  which  we  are  to  work  are  well  understood  and  their  ope- 
ration proven. 

But,  under  the  particular  circumstances  which  we  have,  there  is  a 
question  as  to  how  the  object  can  be  most  cheaply  accomplished. 

To  this  extent  the  work  is  experimental,  and  if  carried  forward 
intelligently  it  cannot  but  result  in  showing,  after  the  flrst  year  or 
two  of  trial,  wherein  economies  may  be  practiced  and  the  object 
attained  at  less  cost,  as  all  river  works  have  before  it. 

SPECIFICATIONS    FOR   BRUSH   AVORKS. 

On  this  day  I  hand  you  specifications  for  brush  dams  on  the  Yuba 
and  Bear  Rivers.  % 

They  are  drawn  for  heavy  dams,  intended  to  become  rapidly  imper- 
meable as  the  muddy  water  flows  over  them,  and  upon  the  principle 
heretofore  laid  down.  In  my  opinion,  it  will  be  necessary  to  put  such 
structures  at  least  across  all  open  channels  where  the  force  of  the  cur- 
rent at  flood  time  is  to  be  resisted,  and  it  is  intended  to  cause  a  deposit 
for  the  full  width  of  the  stream,  in  other  words  to  store  the  detritus 
above  the  dam. 

Where  the  line  of  a  dam  is  located  through  a  heavy  growth  of 
brushwood  or  young  timber  the  character  of  the  structure  may  be 
changed  so  as  to  effect  a  material  saving  in  construction. 

A  belt  of  such  timber  left  standing  forms  a  dam  for  our  purposes 
itself,  and  taken  as  the  framework  of  a  permeable  dam,  this  kind  of 
a  stifc^cture  might  be  put  up  through  such  a  belt,  at  very  moderate 
€Ost,  in  line  with  the  heavier  "dams  across  the  open  channels. 
_  I  do  not  attempt  to  draw  specifications  for  this  class  of  work  at  this 
time.  Indeed,  so  much  will  depend  upon  the  exact  character  of  the 
growth  itself,  that  it  will  be  necessary  to  examine  each  line  in  detail 
before  any  such  attempt  can  be  made  to  advantage. 

When  the  lines  of  the  proposed  dams  can  be  gone  over  after  the 


29 

water  has  fallen  somewhat  more,  I  will,  if  desired,  make  specifica- 
tions as  are  required. 

Difficulty  of  describing  river  toorks  in  detail  before  construction. 

Here  let  me  call  attention  to  the  difficulty  of  drawing  a  description 
of  such  works  sufficiently  in  detail  upon  which  to  contract. 

The  best  laid  plans  for  this  class  of  river  works  have  almost  always 
to  be  changed  to  suit  the  peculiar  circumstances  and  conditions  found 
or  developed  during  the  course  of  operations. 

Frequently  it  may  cost  near  as  much  to  make  the  examinations 
necessary  upon  which  to  base  specifications  for  such  works  as  it  would 
cost  to  do  tlie  work  itself  under  management,  where  there  was  latitude 
for  the  exercise  of  discretion  on  the  part  of  the  engineer  in  charge. 

And  I  desire  to  be  understood  now  as  saying  that  much  must  be 
left  to  the  judgment  of  the  engineer  in  charge,  who,  as  the  work  pro- 
gresses, should  ht  its  details  to  the  conditions  presented. 

For  this  reason. it  would  be  much  better  if  this  work  could  be  done 
by  day  labor  and  not  under  contract;  though  it  is  possible  that  the 
ol3Jections  to  this  arrangement  from  other  causes  would  more  than 
counterbalance  the  advantages  presented  upon  the  score  just  spoken 
of.  And  yet  I  can  not  see  how  the  thousand  and  one  little  jobs  of 
work,  which  I  may  with  truth  call  stitches  in  time,  that  will  have  to 
be  carried  forward  by  your  Engineer,  can  be  done  by  contract.  It 
will  cost  as  much  to  advertise  some  of  them  as  it  will  to  do  them. 

Very  respectfully,  your  obedient  servant, 

WM.  HAM.  HALL, 

State  Engineer. 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
BERKELEY 

Return  to  desk  from  which  borrowed. 
This  book  is  DUE  on  the  last  date  stamped  below. 


9> 


\^^ 


6V*« 


^^C 


I^OV  1  2  1969  44 


MAR    4  1978. 

HapuiFCB    578 


Xl^^"" 


'69 


.9N* 


LD  21-100m-ll,'49(B71468l6)476 


:;!iii^^H      Gaylord  Bros. 

Makers 

Syracuse,  N.  V 

PAT.  JAN.  21,  1908 


M   r   RFRKFLFY  LIBRARIES 

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